Because of their commanding properties, ultrashort and short peptides are gaining significance as viable candidates for molecular self-assembly, which is a naturally inspired approach for developing supramolecular structures and can be used to design various strategies of significance in the field of biomaterials. Self-assembly of biomolecules like proteins, lipids, and nucleic acids is observed in living organisms, various biological-process-based examples like amyloid-β plaque formation, lipid bilayer assembly, and the complementary binding of the nucleotide bases of nucleic acids involve self-assembly. Among all biomolecules, peptide-based self-assembly has the advantage of the availability of the source, peptides can be easily synthesized or obtained from the natural degradation process and can be engineered to modulate their action, making them an area of immense interest for research. Multiple modification options provide a wide area for the engineering of amino acid sequences. Understanding of the amino acid residues with their existing properties and modified properties is very helpful for further improvements. Computational approaches like molecular dynamics simulations provide atomistic-level insight into the self-assembly process, by which newer physical-chemical modifications can be planned. Virtual screening of the peptides on the basis of their properties and probability for the desired activity are helpful as well. Engineered and programmed peptides have been reported for various applications like drug delivery and target specific formulations. A combined approach of computational and experimental studies is helpful to understand and optimize the self-assembly process and mechanism at the atomic level. These self-assembled ultrashort peptides have been used in a wide range of applications from hydrogels to drug delivery agents, biosensors, emulsifiers, and so on.

Peptides are signaling epitopes that control many vital biological events. Increased specificity, synthetic feasibility with concomitant lack of toxicity, and immunogenicity make this emerging class of biomolecules suitable for different applications including therapeutics, diagnostics, and biomedical engineering. Further, chitosan, a naturally occurring linear polymer composed of D-glucosamine and N-acetyl-D-glucosamine units, possesses anti-microbial, muco-adhesive, and hemostatic properties along with excellent biocompatibility. As a result, chitosan finds application in drug/gene delivery, tissue engineering, and bioimaging. Despite these applications, chitosan demonstrates limited cell adhesion and lacks biosignaling. Therefore, peptide−chitosan hybrids have emerged as a new class of biomaterial with improved biosignaling properties and cell adhesion properties. As a result, recent studies encompass increased application of peptide−chitosan hybrids as composites or conjugates in drug delivery, cell therapy, and tissue engineering and as anti-microbial material. This review discusses the recent investigations involving chitosan−peptide materials and uncovers various aspects of these interesting hybrid materials for biomedical applications.

The rhodium(III)-catalyzed direct C−H addition and annulation of benzimidates and aldimines with β-(trifluoromethyl)-α,β-unsaturated ketones is described. This protocol provides the facile and efficient formation of various trifluoromethyl-containing indenamines or aminoindanes in moderate to high yields.I ndenes and indanes are very important carbocyclic derivatives that are found in various natural products and pharmaceutically active molecules. 1 Moreover, they find application in organometallics and material science. 2 In particular, aminoindene/indane derivatives have shown important biological activities, 3 such as glutamate receptor antagonist, calcium antagonist, and anti-Parkinson. In addition, trifluoromethyl-containing indane acts as a selective CB2 ligand (Figure 1). 4

Bone-specific functionalization strategies on liposomes are promising approaches to delivering the drug in osteoporotic conditions. This approach delivers the drug to the bone surface specifically, reduces the dose and off-target effects of the drug, and thereby reduces the toxicity of the drug. The purpose of the current research work was to fabricate the bone-specific peptide conjugated pegylated nanoliposomes to deliver anabolic drug and its physicochemical evaluations. For this, a bone-specific peptide (SDSSD) was synthesized, and the synthesized peptide was conjugated with a linker (DSPE-PEG2000-COOH) to obtain a bone-specific conjugate (SDSSD-DSPE). Purified SDSSD-DSPE was characterized by HPLC, Maldi-TOF, NMR, and Scanning Electron Microscope/Energy Dispersive Spectroscopy (SEM/EDS). Further, peptide-conjugated and anabolic drug-encapsulated liposomes (SDSSD-LPs) were developed using the ethanol injection method and optimized by Central Composite Design (CCD) using a statistical approach. Optimized SDSSD-LPs were evaluated for their physicochemical properties, including surface morphology, particle size, zeta potential, in vitro drug release, and bone mineral binding potential. The obtained results from these studies demonstrated that SDSSD-DSPE conjugate and SDSSD-LPs were optimized successfully. The particle size, % EE, and zeta potential of SDSSD-LPs were observed to be 183.07 ± 0.85 nm, 66.72 ± 4.22%, and −25.03 ± 0.21 mV, respectively. SDSSD-LPs demonstrated a sustained drug release profile. Further, the in vitro bone mineral binding assay demonstrated that SDSSD-LPs deliver the drug to the bone surface specifically. These results suggested that SDSSD-LPs could be a potential targeting approach to deliver the anabolic drug in osteoporotic conditions.

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: The most common reason behind dementia is Alzheimer’s disease (AD) and it is predicted to be the third lifethreatening disease apart from stroke and cancer for the geriatric population. Till now only four drugs are available in the market for symptomatic relief. The complex nature of disease pathophysiology and lack of concrete evidences of molecular targets are the major hurdles for developing new drug to treat AD. The the rate of attrition of many advanced drugs at clinical stages, makes the de novo discovery process very expensive. Alternatively, Drug Repurposing (DR) is an attractive tool to develop drugs for AD in a less tedious and economic way. Therefore, continuous efforts are being made to develop a new drug for AD by repursing old drugs through screening and data mining. For example, the survey in the drug pipeline for Phase III clinical trials (till February 2019) which has 27 candidates, and around half of the number are drugs which have already been approved for other indications. Although in the past the drug repurposing process for AD has been reviewed in the context of disease areas, molecular targets, there is no systematic review of repurposed drugs for AD from the recent drug development pipeline (2019-2020). In this manuscript, we are reviewing the clinical candidates for AD with emphasis on their development history including molecular targets and the relevance of the target for AD.

Dipeptides are minimalistic peptide building blocks that form well ordered structures through molecular self-assembly. The driving forces involved are cooperative noncovalent interactions such as π–π stacking, hydrogen bonding, and ionic as well as hydrophobic interactions. One of the most intriguing self-assembled motifs that has been extensively explored as a low molecular weight hydrogel for drug delivery, tissue engineering, imaging and techtonics, etc. is Phe-Phe (FF). The backbone of the dipeptide is very crucial for extending secondary structures in self-assembly, and any subtle change in the backbone drastically affect the molecular recognitions. The squaramide (SQ) motif has the unique advantage of hydrogen bonding which can promote the self-assembly process. In this work we have integrated the SQ unit into the dipeptide FF backbone to achieve molecular self-assembly. The resulting carbamate protected backbone modified dipeptide (BocFSAF-OH, 10) has exhibited molecular self-assembly with a fibrilar network. It formed a stable hydrogel (with CAC of 0.024 ± 0.0098 wt %) via the solvent switch method and was found to possess excellent enzymatic stability. The dipeptide and the resulting hydrogel were found to be cytocompatible. When integrated with a polysaccharide based biopolymer, e.g. sodium alginate, the resulting matrix exhibited strong hydrogel character. Therefore, the dipeptide hydrogel of 10 may find its applications in a variety of fields including drug delivery and tissue engineering.